Apparatus and method for the non-destructive measurement of hydrogen diffusivity

Patent metadata

Field	Value
Publication number	US-10809241-B2
Application number	US-201916408668-A
Country	US
Kind code	B2
Filing date	May 10, 2019
Priority date	Apr 28, 2017
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

Apparatuses and methods of measuring a hydrogen diffusivity of a metal structure including during operation of the metal structure, are provided. A hydrogen charging surface is provided at a first location on an external surface of the structure. In addition, a hydrogen oxidation surface is provided at a second location adjacent to the first location on the external surface of the structure. Hydrogen flux is generated and directed into the metal surface at the charging surface. At least a portion of the hydrogen flux generated by the charging surface is diverted back toward the surface. A transient of the diverted hydrogen fluxes measured, and this measurement is used to determine the hydrogen diffusivity of the metal structure in service.

First claim

What is claimed is:

1. A method of measuring a hydrogen diffusivity of a metal structure comprising:
providing a hydrogen charging surface at a first location on an external surface of the structure;
providing a hydrogen oxidation surface at a second location adjacent to the first location on the external surface of the structure;
generating a hydrogen flux directed into the metal surface at the charging surface;

detecting a current representative of a transient of the hydrogen flux diverted back toward the oxidation surface from the metal structure; and
determining the hydrogen diffusivity of the metal structure based on the detected hydrogen flux.

2. The method of claim 1 , wherein the hydrogen charging surface is produced by a first electrochemical cell and the hydrogen oxidation surface is produced by a second electrochemical cell.

3. The method of claim 2 , further comprising adding a coating at the oxidation surface to promote oxidation of hydrogen.

4. The method of claim 3 , wherein the coating includes palladium.

5. The method of claim 2 , further comprising measuring an oxidation current in the oxidation cell in order to measure the transient.

6. The method of claim 1 , wherein the hydrogen diffusivity is determined from the transient of hydrogen flux using a direct simulation technique based on a Fickian diffusion model that uses initial conditions based on an experimental apparatus.

7. The method of claim 6 , further comprising:
setting a value for the hydrogen diffusivity;
executing the diffusion model using the set value of hydrogen diffusivity;
comparing results of the Fickian diffusion model to results using the experimental apparatus; and
repeating the previous steps with different values of hydrogen diffusivity until a closest match between the results of the diffusion model and the results using the experimental apparatus is reached.

8. The method of claim 1 , wherein the hydrogen diffusivity is determined from the transient of hydrogen flux using a simulated master graph for a particular experimental apparatus design, the simulated master graph being independent of geometric dimensions, and experimental parameters.

9. The method of claim 8 , further comprising:
performing sensitivity analysis on each geometrical parameter to determine an influence of the parameter on a normalized transient curve; and
identifying the curve as a master curve, with respect to a parameter, if the curve is invariant to changes in the parameter.

10. The method of claim 9 , wherein the parameters include at least two of the following: metal structure thickness, a size of the charging surface, a width of the oxidation surface and a wall thickness of the charging cell.

11. The method of claim 1 , wherein the measurement of hydrogen diffusivity is performed while the metal structure is in service and operational.

Assignees

• Saudi Arabian Oil Co

Inventors

• Traidia Abderrazak
• Alshahrani Mohammed
• Duval Sebastien A

Classifications

• G01N2001/2241

  purpose-built sampling enclosure for emissions · CPC title

• G01N33/2025 Primary

  Gaseous constituents · CPC title

• G01N27/413

  Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells} · CPC title

• G01N13/00 Primary

  Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects (scanning-probe techniques or apparatus G01Q) · CPC title

• C25B1/02

  Hydrogen or oxygen · CPC title